The present invention relates to a means for operating tightly fitting windows, doors, hatches and the like, (such as skylights, sliding doors and hatches for watertight bulkheads) with the help of an electric motor fitting adjacent the skylight, or the like, effecting movement on outer parallel rails and inner parallel rails attached on the window frame, or the like.
When opening and closing skylights, for instance, considerably more force is required in the initial stage than in the continued opening or closing process. Mechanism for operating skylights and the like are therefore normally designed for the first amount of force necessary which means that motors and gears, for instance, are designed to be relatively powerful and are therefore expensive.